Sound amplifier



June 14 1927.

H. W. PLEISTER SOUND AMPLIFIER FiledFeb. 29, 1924 2 Sheets-Sheet l f, mwm

Jun? 14 1927 H. W. PLEISTER SOUND AMPLIFIER .Filed Feb. 29, 1924 2 sheets-sheet 2 Patented .lune 14, 1927.

UNITED STATES HENRY W. PLEISTER, OF WESTFIELD, NEW JERSEY, ASSIGNOR T HENRY B. NEWHALL.

PATENT OFFICE.

SOUND AMPLIFIER.

Application led February 29, 1924. Serial No. 695,974.

My present invention relates to an im provement in sound amplifying devices which may be utilized in combination with sound reproducing devices, such as phonographs, and the like, but is more specifically intended to be utilized as a loud speaking device in combination with radio receiving sets.

One of the advantages of my present iniln provement relates to the mounting ofcertain elements ofthe amplifying device, to be hereinafter'known as a regonator, and contemplates amongst other advantages the main advantage of mounting the component lf elements of the resonator including the sound reproducing device in a manner that permits each one of these to be independentlymounted one from the other so that each of these elements will have substantially no physical Contact one with the other,

thereby permitting each of the coacting elements thereof to resonate independently one of -the other, thereby to improve-the tone quality of the resonator in its entirety. As

will 'oe hereinafter described, modifications of this underlying principle on the score of greater economy in manufacture are disclosed and they include the underlying principles of my invention.

Another advantage of my device consists in the provision of means whereby certain of the coacting resonator elements may be adjustably mounted one from the other so that variations in relative position of the coacting elements may be made, thereby attaining modifications of tone from a full clear volume to a minimum or reduced tone volume, which advantage in the case of radio reception obviates the necessity for changing the tuning of the radio receiver and thus keeps the tone qualities of the device While producing its volume to any desired degree, without' vaffecting its clarity.

Another advantage of my improvement lies in the method of mounting the tone reproducer device to the coacting resonator elements so that it may be resiliently mounted thereto as desired.

These and other improvements will be disclosed as the specification proceeds, and it will be obvious that improvements may be made in the herein disclosed structure withv out departing from the spirit or scope of the invention.

In the drawings, Fig. 1 is a front View 0f one form of my device;

Fig. 2 is a sectional View thereof, taken on the line 1-1 of Fig. l, looking in the direction of the arrows of said line;

Fig. 3 is a rear elevation of the device shown in Fig. 1;

Fig. 4 is a fragmentary view of one of the element adjusting means.

Fig. 5 is an axial vertical sectional view of another form of the disk showing a modified form of adjustment of one of the elements; v Figs. 6 and 7 are sectional views showing modified forms of the minor resonator element shown in Figs. 2 and 5;

Fig. 8 is a front View of another modification of my device;

Fig. 9 is a partial sectional view taken on the line 8-8, Fig. 8;

Fig. 10 is a rear elevation of another form of the device;

Fig. 11 is a sectional view taken on the line 10-10, and

Fig. 12 is a fragmentary perspective view of the adjustment means for varying the position of one of the coacting elements of the devices of Figs. 8 to 10.

My improvement consists in the provision of a comparatively shallow wide mouthed resonating device which in its complete assembly, as shown in Fig. ,1, comprises an outer frame or support l, which is preferably provided with an orifice of concave form and generally denoted by 2, Fig. 2, the concavity therein being of such a nature as to permit of the placing therein of a bowl-like major sound reflecting element 3, Fig. 2, and it will be" noted in the said figure that at no point does the element 3 come in contact with the base member 1, by reason of the air space 4 shown between the back of the element 3 and the concave kface of the opening tube of the face mem- By referring to Fig. 3, it' will be noted that the bowl-like member 3 at its rear is mounted upon a flexible cross strip 5, which strip performs two functions, one of which is to support the major reflector 3 in operative position in the opening 2 in a rather flexible or resilient manner and also to support therein a telephonie or tone transmitting element 6, which element is shown in Fi 2 and 5 only in operative position.

'n the bowl-like major resonating element 3 is placed a minor tone deflector element 7 having a curved forward face 8 of irregular convex form so that the tone space lio ' element 7 in and 9, is of a somewhat tapering horn-like construction in one-half section thereof, but owing to the circular construction of the coacting elements, the air column in the tone space 9 and which is acted upon by the sound transmitting device is narrower immediately in front of the soundtransmitting device 6 as at 10, and gradually increases in a diverging manner near the outer faces of the two coacting tone elements 3 and 7 so'that in effect, the tone chamber so formed is diverging from adjacent the tone reproducing element to the front outer confines of the instrument.

While I have shown in each instance of the disclosure herein the device as being made substantially circular, this is merely' a concession to the easy manufacture of this device, which is intended to be primarily made of wood and may therefore be lathe turned, but in actual construction the circular elements here shown may be rectangular or in other desired form so long as they maintain a substantially narrow front to rear width, and directly develop a diverging tone space or chamber 9.

Referring back to the convexed minor tone deflecting element 7, it will be noted in Fig.

I 1 that it is rovided with an adjusting screw generally enoted by A, this said screw being firmly affixed to the center yof the element as shown in Figs. 2 and 5, in such a manner as to permit, by manipulating the knurled head B, Fig. 2, of adjusting the out or to and from the tone reproducer 6. To this end a preferably metal arm C which is firmly affixed by means of screws D, Fig. 1, to the base portion of the frame 1, has provided at its upper end a boss E in which is threadedly received the adjusting screw A, and a lock nut F maybe provided, whereby,l the minor element as shown in Fig. 2 may be adjusted toward or from the sound element 6.

The foregoing description applies also to the fragmentary view, in Fig 4, which is a view of the adjusting device shown slightly enlarged for ease of apprehension.

From the foregoing descri tion it will be noted that each of the `relate sound devices forming the resonator proper, and comprising elements 3 and 7, are independently mounted one from the other in such a way that they may be ad'ustably related one to the other thereb7 to deflect sound forwardly from the large open passage 9 thereof, and that each of these elements is free to vibrate independently one of the other and in its natural. periods of resonance without interference one with the other. It will also be noted that by adjusting the minor element 7 to and from the resonator 3 the volume may be considerably cut-down or reduced or increasedi'n volume by the closeness `of the adjusting of the said element 7, and this means also provides a method whereby the tone may be sharpened or made fuller, according to desire.

In Figs. 6 and 7, there are shown fragmentary portions of the minor resonator element 7 in which the convexity of the inner deflecting face of the said element is somewhat similar to the faces shown in Figs. 2 and 5, with the exception that the deflecting /surface immediately adjacent the tone transmitting device 6 is modified at the apex 11 and 12, Figs. 6 and 7 respectively, in such a manner as to provide a means for cutting down further the amount of air space im- 'mediately adjacent the tone transmitter 6, and these modifications permit of changes of tone quality and volume during the adjustment of the element 7 as above described.

Fig. 5 shows a modification of the minor element adjustment means as shown in Fig. 2, to the extent that the upright C is lixedly mounted in the element 7 by a right-angled bend G and is provided with a pin generally denoted by B', which is frictionallyengaged in a bushing E held by a nut E2 in the base portion of the frame 1. By pulling out the pin adjusting means there shown, the amplifier may be brought out to the dotted position, generally denoted by 12, Fig. 5. A pin Es secured diametrically through the ushing and received in a longitudinal slot B2 in the pin B holds the upright 11 and the element 7 against lateral movement relative to the axis ofthe major reflector.

In Fig. 8, there is shown a modification of my device in which while there are slight differences in the structural details of the device, different means of mounting are also provided whereby the minor deflector element 7 therein may be adjusted as previously described, but means are also provided for the complete removal of the minor deflector element 7.

In the modifications lshown in Figs. 8 to 11 inclusive, the same indices are indica-ted for similar arts as were indicated for the 1 to 3 mclusive.

n the matter of modifications shown in the last noted fifures, the frame or base element 1 is provided near its bottom with an outstanding post P whichv carries therein an upright C which in turn as shown in Fig. 12 has at its upper end thereof a U-shaped rest iece R in which U-shaped piece R is slida 1e and removabl mounted an adjusting stem S, one end o which is flanged and attached to the minor deflector element 7 by means of screws T entering the said flange U.

At the side of the rest bearing R is rovided a cone pointed thumb screw V w lich may be screwed in or out to release the rod S when it is desired to adjust the element 7 toward orl from the resonator 3. and this adjustment is done by loosening the said thumb screw V and sliding the rod S toward or from the device and locking the y said screw again to hold it in said adjusted position.

In Fig. 11, there is shown a further modification of the method of mounting the coactin elements so that each element thereof may ave relative free vibration one from the other, thus giving each 'element an opportunity to vibrate independently, it having been found that such independent mounting for self vibration improves the tone of the device greatly.

In addition to the method of mounting the minor dellector element 7, in the views of Figs. 10 and 11 in a manner yexactly as outlined for Figs. 8 and 9, the sound transmitter 6 is also independently mounted by having a post element W mounted at the rear of the frame or base portion 1, and in it is mounted a standard X which is suitably affixed to ythe sound transmitter G whereby the said sound transmitter will be held independently of the major resonance element 3 so that this element and its resilient lnounting strip 5 are held independently both of the sound transmitter 6 and the minor sound deflector 7.

By mounting the device as shown herein, it has been found :hat a better tone quality is created, being free and clear of the usual tone qualities from devices of this type where the sound transmitter and the amplifyin horn or equivalent are afhxed to one another and in which latter described devices, owingv to the integral combination of the coacting parts with each other, there ensues a peculiar ,tubbiness of tone due to the assembly of Yeach of these devices, one to the other without giving play to the natural periods of resonance that are created therein during use.

A further advantage will be noted from the modifications shown in Figs. 8 to 11 inclusive, and this improvement relates to the thickness of the minor element 7 and the major element 3 where it will be noted that these portions while being convoluted in such a manner as to form in sectional view a. megaphonic annular diverging sound chamber 9, the walls of both elements are considerably thin so that in effect they are somewhat Shell-like in their structure. this end it will be noted, for instance, in F ig. 9 that the minor sound deflector element 7 has its back wall generally denoted by 13 from the inside deector contour in a substantially even thickness so that the deflector element 7 has a different period of resonance than with the deflector 7 shown in Figs. 2 and 5.

The foregoing also applies to the major resonator 3, the back wall of which as at 14 also follows, substantially the inside sound deflector face so that it is also shelllike in its construction, and this further adds to the clarity of tone resonance, as well as adding to the ornamental appearance of this device when viewed from both the front and rear.

I have made both of these devices in actual practice in both forms shown herein, and in view of the fact that both of these devices are made of wood throughout, eX- cept as to the metallic adjusting supporting means herein described. I have found that the points above outlined, result in a highly improved so-called loud speaker device as adapted in its use for radio reception and amplification. Furthermore I have found by making my device of wood, as herein disclosed, although not limited to the use of this material, it is possible to create a thin or narrow wall of substantially ornamental appearance, being polished and tre-ated as any article of household would bc, the utility of the device in its sufficient operation, is heightened by the ornamental furniture effect created.

I claim:

1. In combination, an outer frame rovided with a wide intramarginal orifice aving a forwardly diverging concave wall; a forwardly opening bowl-like reflector resiliently mounted at its mid part in said orificeand spaced from but almost touching said concaved wall and provided with a central opening; and a means resiliently mounting a telephonic element transmitting sound into said opening.

2. In combination, a frame; a forwardly opening bowl-like reflector resiliently mounted at its mid part in said frame and provided with a central opening; and means adapted to receive an element transmitting sound into said opening.

3. In combination, a frame; a reflector in said frame adapted to receive sound from an element transmitting sound into said reflector; and a minor tone deflector disposed in said reflector and resiliently mounted on said frame cooperating with said reflector to form a flaring opening.

4. In combination, a frame; a forwardly opening bowl-like major reflector in said frame and adapted to receive sound from an element transmitting sound into said bowl; a minor tone deflector disposed in said reflector and cooperating with said reflector to form a forwardly flaring opening; and means including a metal arm secured kon the front of said frame for resilientlysupporting the deflector in the reflector.

5. In combination, an outer frame provided with a wide intramarginal orifice; a cross strip securedv across the back of the frame and provided with an opening coaxial with said orifice; a forwardly opening bowl-like reflector disposed insaid orifice spaced from said frame; said reflector being secured at its mid part to said strip and provided with an opening registering with said opening of the strip.

6. In combination, a major reflector; means for mounting an element for transmitting sound into said reflector; and a' flector resiliently mounted on said support;

and a minortone deflector disposed in said reflector and cooperating with said reflector to form a flaring opening; said element and deflector being also resiliently mounted on the support.

8. In combination, an outer framev rovided with a wide intramarginal orifice aving forwardly diverging lconcave walls; a forwardly opening bowl-like major reflector resiliently mounted at its mid part in said orifice and spaced from, but almost touching, said concave wall and provided with a central opening; a resiliently mounted member adapted to support a telephonie element transmitting sound into said opening; a minor tone deflector disposed coaxially in said reflector and having a concave rear face cooperating with said reflector to form an annular opening of forwardly flaring horn-like shape in axial half-section; and means including a metal arm secured on the front of said frame for resiliently supporting the deflector in the reflector.

9. In combination, an outer frame rovided with a wide intramarginal orifice aving forwardly diverging concave walls; a thin cross strip secured across the back of the frame; a forwardly opening bowl-like major reflector disposed in said orifice spaced from, but almost touching, said concave Wall; said reflector being secured at its mid part to said strip andl provided with a central openino; means to mount a telephonic element 1n position to transmit sound into said opening; a minor tone deflector disposed coaxially in said reflector and having a concave rear face cooperatin with said reflector to form an openin whio in axial half-section, is of forwar ly flaring hornlike shape, narrowest at said opening and has a gradually increasing flare; and adjusting means supporting said deflector and including a metal arm secured on the front margin of said frame for adjusting the position of said deflector relative to the reflector.

10. In combination, a frame adapted to support a soundtransmittin element direct- 1n sound away from sai frame; and a reector resiliently mounted in said frame and receiving sound from said element.

11. In combination a forwardly openin bowl-like reflector having a thin edge; an an outer frame supporting said reflector and provided with a thick rigid strong part spaced from and almost touching and protectin said edge.

12. n comblnation, a frame adapted to support a sound transmitting element mounted on said frame; and sound reflecting means for'reflecting sound from said element; all of the reflecting means being resiliently supported on the frame.

13. In combination, a frame adapted to support a sound transmitting element mounted on said framea major reflector resiliently mountedin said frame for receiving sound from said element; and a minor tone deflector resiliently disposed in said reflector and cooperating with said reflector to form an amplifying opening; said deflector being free of support except substantially at its middle part.

14. In combination, means adapted to support a sound transmitting element; a major reflector for receiving sound from said element; and a minory tone deflector resiliently disposed in said reflector and cooperating with said reflector to form an amplifying opening; said deflector beingrentirely free of sup ort near its periphery.

15. n combination, a support; a reflector mounted on said support; a minor tone deflector disposed in said reflector and coopereratin with said reflector to form a sound ampli ying opening; a stem secured fast on the front of the deflector; and a metal arm secured on the front of the support adjust. ably supporting said stem.

16. In combination, a support; a major reflector mounted on said sup ort; a minor tone deflector disposed in sai reflector and cooperating with said reflector to form sound amplifying opening; a stem axially secured fast on the front of the deflector; an upright metal arm secured on the front of the support and provided with a seat member at its free end receiving said stem; and a clamping means on said member engagin said stem.

17. n combination, a frame; means adapted to support a sound transmitting element mounted on said frame; a major reflector mounted in said frame and for receiving sound from said element; a minor tone deflec'tor dis osed in said reflector andcooperating with said reflector to form an amplifying opening; a stem secured fast on the front of the deflector; an upright 'metal arm secured on the front of the frame and provided with a U-shaped seat member at' its free end receiving said stem; and a. thumb-screw screwed in said seat member and engaging said stem.

Signed at New York, in the county of New York and State of New York, this 21st day of February, A. D. 1924.

HENRY W. PLEISTER.

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